Adjustable strap connector



Nov. 24, 1964 A. Y. WARNER ETAL 3,157,929

ADJUSTABLE STRAP CONNECTOR Filed May 22, 1962 N 9 SR M l 7 R V ON A 2 mm m 4. a /45W 55 W Y TS M u N U V E E DL N mmw R m 4 W A Q 4 W H L m 6 a 4 L 4 2 a M 2 G F United States Patent 3,157,929 ADJUSTABLE STRAP QONNEQTQR Alden Y. Warner, Farmington, Wilbur .l'. Craven, East Hartford, and .iohn Stacherl, New Britain, Conan, assignors to The Capeweli Manufacturing Company,

Hartford, Conn, a corporation of Connecticut Filed May 22, 1962, Ser. No. 196,759

3 Claims. (Cl. 24 -196) This invention relates to belt or strap connectors, and more specifically to an improved belt or strap connector for adjustably securing the end of a strap or webbing and having particular utility in safety belt buckles.

This application is a continuation-in-part of our copending application, Serial No. 163,255, filed December 29, 1961.

One of the objects of the present invention is the provision of an improved adjustable strap connector which will effect a secure connection capable of successfully withstanding relatively great loads even when suddenly applied thereto and of insuring against slippage of the strap both under heavy loads which highly tension the strap and under relatively small loads.

Another object is the provision of an adjustable strap connector which will prevent slipping of the strap therein under heavy loading without injurious abrading or cutting of the strap, and consequently, without diminishing the strength or margin of safety of the strap even after extended usage.

A further object is to provide such an improved ad- 7 justable strap connector which can be easily manipulated and which is relatively simple in construction and which may be readily and economically fabricated and assembled.

Other objects will be in part obvious and in part pointed out more in detail hereinafter.

The invention accordingly consists in the features of construction, combination of elements and arrangement of parts which will be exemplified in the construction here after set forth and the scope of the application which will be indicated in the appended claims.

In the drawing:

FIG. 1 is a perspective view of a safety belt buckle assembly embodying the present invention wherein the strap has been broken away for purposes of clarity;

FIG. 2 is a fragmentary side elevational view of the safety belt buckle of FIG. 1 with the side wall partially broken away to show the operative elements of the strap connector in a strap-adjusting position;

FIG. 3 is a view generally similar to FIG. 2 showing the operative elements of the strap connector in straplocking position;

FIG. 4 is a fragmentary bottom view of the rear portion of the safety belt buckle with a portion of the strap cut away; and

FIG. 5 is a fragmentary bottom view, similar to FIG. 4, showing a modification of the invention.

Referring in detail to the attached drawing, a safety belt buckle embodying the present invention is generally comprised of the frame unit or buckle designated by the letter A and the separable fitting designated by the letter B and which is engageable in the forward end of the buckle A to connect together the two straps 2 and 4. The end portion of the strap 2 is looped through the aperture 6 of the separable fitting B and then the overlapping portions secured together (not shown) in any convenient manner such as stitching to thereby permanently position fitting B therebetween.

The buckle A has an elongated, generally channelshaped frame 8 with a bottom wall it) and integral upstanding side walls 12 and 14. The latch cover 16 is pivotally mounted on the side walls 12 and 14 by pivot 3,157,929 Patented Nov. 24, 1964 pins 18 and encloses suitable latching mechanism for firmly engaging the separable fitting B, the illustration of which has been omitted for purposes of clarity. A highly effective latching mechanism is illustrated in detail in our Patent No. 2,999,288 issued September 12, 1961.

Referring now in detail to the rearward portion of the buckle A which is constructed in accordance with the present invention to provide an adjustable connection for the end of the strap 4, the bottom wall 10 of the frame 8 has a transverse strap-receiving aperture 20 providing a stationary gripping face 21. As most clearly shown in FIG. 4, relief cut-outs 19 are provided in the adjoining edges of the side walls 12, 14 and bottom wall 10 which define the corners of the strap-receiving aperture 20 for a purpose to be described hereinafter.

Slidably carried in the frame 8 above the aperture 20 is a cross member 25 which has projecting end portions 26 loosely received in parallel, generally longitudinally extending slots 23 in the side Walls 12 and 14. As can be seen in FIGS. 2 and 3, the plane of the bottom surface of the cross member 25 is spaced above but closely adjacent the bottom wall it). The periphery of cross member 25 is defined by a plurality of discontinuous and generally alternating flat and convex surfaces (for a purpose to be described more fully hereinafter) including the movable convex gripping face 27 at its lower rear ward edge cooperable with the stationary gripping face 23. and the gripping shoulder 22 on the upper surface of the bottom wall 19 adjacent thereto. Spaced upwardly of the gripping face 27 is the projecting ledge portion 29 which extends rearwardly of the frame and has a convex outer surface 30.

The slots 23 in the side walls 12 and 14 are dimensioned to permit the cross member 25 to move from a position forwardly of the stationary gripping face 21'to a position wherein the'ledge portion 29 extends rearwardly thereof. As best seen in FIGS. 2 and 3, the slots 23 also are slightly inclined rearwardly and downwardly of the frame 8 and are dimensioned sufiiciently larger than the end portions 26 to permit limited pivotal movement of the elongated cross member end portions 26, and thereby the cross member 25, about their longitudinal axis while preventing rotation thereof for a purpose to be fully described hereinafter.

Although the des-ired peripheral configuration of the cross member 25 may be provided in a single element by extrusion or machining, the cross member 25 is most conveniently fabricated from a body portion 32 and a bar portion 34 press fitted into a longitudinal groove 36 in the body portion 32 as shown in the illustrated embodiment. The bar portion 34 is of sufficient length so that its ends project beyond the ends of the body portion 32 to provide the end portions 26 of the cross member 25 which project into the slots 23. This two-piece construction permits the cross member 25 to be economically and effioiently fabricated and assembled to the frame 8 by first seating the ends of the bar portion 34 in the slots 23 and then press fitting the bar portion 34 into the longitudinal groove as of the body portion 32.

The surface of the cross member 25 is smooth and unknurled or otherwise roughened to eliminate abrasive action upon the strap 4 although a desirable increase in frictional engagement is preferably provided by utilizing a body portion 32 of aluminum having an anodized surface. In such a construction, the bar portion 34 of the cross member conveniently is formed from chromeplated steel for optimum strength although the bar portion may be formed integrally with the body portion 32 is so desired.

In assembly, the free. end portion 4' of the strap 4 is inserted upwardly through the strap-receiving aperture 20 forwardly of the cross member 25, looped over and around the cross member 25, passed out the strap-receiving aperture 20 and doubled back upon itself so that the free end portion 4 of the strap overlies the continuous or main body portion thereof.

When tension is applied to the continuous or main body portion of the strap 4 as denoted by the arrow T in FIG. 3, the cross member 25 slides rearwardly of the frame 8 in the direction of the stationary gripping face 21 into the position shown in PEG. 3. During this movement, the ledge portion 29 of the cross member 25 forces the strap 4 rearwardly of the stationary gripping face 21 and the strap is firmly clamped between the movable gripping face 27 at the lower rearward edge of the cross member 25 and the adjacent surfaces of the stationary gripping face 21 and gripping shoulder 22. The displaoement of the strap 4 rearwardly of the stationar gripping face 21 by the ledge portion 29 causes the strap to infiect about the edge of the shoulder 22 thereby increasing the wedging action and area of wedging provided by the cooperating surfaces. As can be appreciated, the greater the tensioning force applied to the strap, the greater will be the wedging or clamping force exerted upon the strap between the cooperating gripping surfaces 21, 22 and 27.

As previously pointed out, the slots 23 are dimensioned to permit limited pivotal movement of the cross member 25 about its longitudinal axis. Upon the application of tension to the strap 4, the cross member 25 pivots counterclockwise (as viewed in the drawings) so as to slightly elevate and position the movable gripping face 27 of the cross member 25 above the cooperating stationary surfaces 21, 22 to provide optimum gripping of the strap 4 without significant abrasive action. The upper edge of the stationary gripping face 21 is most desirably provided with a slight radius, as shown in the drawing, to minimize abrasive action. Such a radius can be provided conveniently by tumbling the frame with abrasives during fabrication.

Additionally, tensioning of the strap causes that portion of the strap looped around the cross member 25 to conform closely to the peripheral shape thereof with the result that a plurality of inflections E, F, G, and H are formed in the strap 4 which increases the frictional engagement therebetween and thereby reduce any tendency of the strap to slip thereover. Although the strap 4 is subject to great slip-resisting inflection under tension, the concave surfaces about the periphery of the cross member 25, including the edge 30 of the ledge portion, are not sharp or abrasive and, hence, provide firm engagement of the strap without the use of abrasive knurling or cutting edges heretofore employed. Additionally, the relatively abrasion-free nature of the entire surface of the cross member 25 as aforedescribed effectively avoids abrasion and rapid wear on the strap.

When the strap is clamped between the stationary and movable gripping faces, transverse growth of the strap caused by compression thereof during clamping action between the gripping faces 21 and 27 is accommodated by the relief cut-outs 19 located at the corners of the strap-receiving aperture 20, as best seen in FIG. 4. In this manner, the edges of the strap 4 will not engage the corners of the aperture 29 and any cutting or abrading action of the edges of the strap by the corners of the strap-receiving aperture 20 and the edges of the strap is precluded.

FIG. 5 shows a modification of the invention in which an alternative means is provided to accommodate the transverse growth of the strap 4 caused by the compression thereof during clamping action between the gripping faces 21 and 27. In the modification of FIG. 5, the gripping face 21 is provided with a transverse curvature to increase the length thereof so that the edges of the strap do not contact the corners of the aperture 20. It is preferred that the transverse curvature have a generous radius of the order of, say, at least several times the width of the strap 4 since this will accommodate the transverse growth 4. of the strap without significantly affecting the longitudinal stress gradient of the strap from one edge to the other. It will be apparent that the curvature of gripping face 21 may he used alone are in conjunction with relief cut-outs 19 as desired.

This cooperation of the clamping of the strap 4 between the movable gri ping face 27 and the stationary gripping face 21 and shoulder 22 and the multiple inflection of the strap under high tension about the remainder of the cross member 25 is highly effective even under heavy loads. Safety buckles embodying the illustrated embodiment of the'invention have prevented slipping of the strap even when tensioned by a force of approximately six thousand pounds, but, although providing such firm retention of the strap against slippage, have not abraded the strap so as to materially lessen the strap strength and life.

In order to adjust the strap 4 so as to increase the eifective length thereof, the free end portion 4' is merely drawn through the buckle to the desired position. To quickly and easily increase the effective length of the strap, the buckle is tilted relative to the strap in a counterclockwise direction, as viewed in the drawings, and the continuous portion of the strap is merely pulled through the buckle in the direction of the arrow T and into the desired position.

As will be apparent to persons skilled in the art, various modifications and adaptations of the structure abovedescribed will become readily apparent without departure from the spirit and scope of the invention, the scope of which is defined in the appended claims.

We claim:

1. An adjustable strap connector comprising a frame having end walls and a pair of side walls, defining a strap-receiving aperture therein, one of said end walls providing a stationary gripping face extending across the frame between said side walls, a cross-member extending across said frame between said side walls, means mounting said cross-member for limited movement longitudinally of said frame with the plane of the bottom surface of the cross-member spaced above but closely adjacent the plane of the top surface of said one said end walls, said cross-member having a lower edge adjacent said stationary gripping face forming a second gripping face cooperable with the stationary gripping face, said cross-member being movable toward said stationary gripping face to clamp a strap therebetvveen, said stationary and movable gripping faces being transversely contoured to provide a distance therebetween which gradually increases from the center of said gripping faces to the ends thereof.

2. A strap connector comprising a frame having a bottom wall and a pair of side walls, said bottom wall having a strap-receiving aperture therein providing a stationary gripping face extending across the frame between the side walls, a cross-member extending across the frame between said side walls, means mounting the crossmember for movement longitudinally of the frame with the bottom surface of the cross-member spaced above but closely adjacent the top surface of said bottom wall, a strap received through the aperture in the bottom wall around the cross-member and outwardly of the aperture, a transversely extending portion of the bottom surface of the cross-member forming a movable gripping face cooperaole with the stationary gripping face to clamp the strap substantially across the full width of the strap upon application of a force to the strap tending to move the cross-member towards the stationary gripping face, said stationary and movable gripping faces being transversely contoured to provide a distance therebetween which gradually increases from the center of said gripping faces to the ends thereof.

3. A seat belt buckle comprising a channel-shaped frame having a bottom wall and a pair of upstanding side walls, said bottom wall having a strap'receiving aperture therein providing a stationary gripping face extending across the frame between said side walls, a

cross-member extending across the frame and mounted in said side walls for movement longitudinally of the frame with the bottom surface of the cross-member spaced above but closely adjacent to the top surface of said bottom Wall, a strap received through said aperture around the cross-member and outwardly of said aperture, atransversely extending portion of the bottom surface of the cross-member forming a movable gripping face cooperable With the stationary gripping face to provide clamping portions engaging the strap upon application of a force tending to move the cross-member towards the stationary gripping face, the clamping portions of said stationary and movable gripping faces being contoured to provide a distance therebetween which generally increases from the center of said clamping portions to the edges thereof.

References (Iited in the file of this patent UNITED STATES PATENTS 

1. AN ADJUSTABLE STRAP CONNECTOR COMPRISING A FRAME HAVING END WALLS AND A PAIR OF SIDE WALLS, DEFINING A STRAP-RECEIVING APERTURE THEREIN, ONE OF SAID END WALLS PROVIDING A STATIONARY GRIPPING FACE EXTENDING ACROSS THE FRAME BETWEEN SAID SIDE WALLS, A CROSS-MEMBER EXTENDING ACROSS SAID FRAME BETWEEN SAID SIDE WALLS, MEANS MOUNTING SAID CROSS-MEMBER FOR LIMITED MOVEMENT LONGITUDINALLY OF SAID FRAME WITH THE PLANE OF THE BOTTOM SURFACE OF THE CROSS-MEMBER SPACED ABOVE BUT CLOSELY ADJACENT THE PLANE OF THE TOP SURFACE OF SAID ONE SAID END WALLS, SAID CROSS-MEMBER HAVING A LOWER EDGE ADJACENT SAID STATIONARY GRIPPING FACE FORMING A SECOND GRIPPING FACE COOPERABLE WITH THE STATIONARY GRIPPING FACE, SAID CROSS-MEMBER BEING MOVABLE TOWARD SAID STATIONARY GRIPPING FACE TO CLAMP A STRAP THEREBETWEEN, SAID STATIONARY AND MOVABLE GRIPPING FACES BEING TRANSVERSELY CONTOURED TO PROVIDE A DISTANCE THEREBETWEEN WHICH GRADUALLY INCREASES FROM THE CENTER OF SAID GRIPPING FACES TO THE ENDS THEREOF. 